Profit optimization by flattening

In order to optimize my profits, every month I take out 50% of my profit from the last month from my portfolio. I do this in case I have profit.
If I had a losing month, I am replacing half the loss with new money.

With this simple strategy, I can optimize my profits in my quite volatile portfolio. The values to take ou / put in 50% is just my gut feeling out of experience. Now here comes my question: How can I calculate optimized values to take out in case of profit and reinvest in case of loss based on my past performance?

Any help appreciated!